Error in Mongodb replication on aws

I am trying to do replication in Mongodb on aws. I have created two ubuntu instances and ssh into them and initiated replication. However when i am trying to add the second node using rs.add(), it gives the following error-

" Quorum check failed because not enough voting nodes responded; required 2 but only the following 1 voting nodes responded:"

I am following this link to do this http://ift.tt/1hikds8

This link suggests that i have to create three instances first, however i have just created 2 instances. Pls tell me if that is the reason for the error?